Valved closure for sound passages



aNvEqToR ALFRED H.KETTLER ATTORNEY Dec. 6, 1949 A. H. KETTLER VALVEDCLOSURE FOR SOUND PASSAGES Filed om. so, 1948 Patented Dec. 6, 19492,490,133 VALVED CLOSURE FOR SOUND PASSAGES Alfred H. Kettler,Collingswood,

Radio Corporation of America,

Delaware N. 1., assignor to a corporation of Application October 30,1948, Serial No. 57,476

Claims.

This invention relates to sound translating apparatus, and moreparticularly to a mechanical means for preventing the pick up of noiseby sound-powered telephones.

Telephones oi the sound-powered type are particularly adapted for use inmany military applications, such as on battleships, or in otherlocations where there is considerable ambient noise. The sound poweredtelephone, which is employed in a conventional telephone headset, is ofthe reversible type, that is, it operates as a transmitter as well as areceiver. It frequently becomes necessary for a listener to remove hisheadset and lay it down or hang it on a hook. Since the headset usuallyremains connected to the telephone system, undesirable noise is pickedup by the transducers and transmitted into the system, therebyinterfering considerably with the transmission of useful signals toother listeners using telephone receivers which are also connected intothat system.

In some cases, attempts have been made to overcome introducingundesirable signals into the system by connecting a switch between thetelephone receiver and its connection to the telephone system whichpermits the user to disconnect the sound-powered telephone from thesystern when the telephone is not in use. However, the switch is not aspositive a means of preventing noise from being fed into the system aswould be desired, for, as in many cases, the user might leave his postand forget to disconnect the instrument from the line, thereby creatinga condition which permits introducing undesirable noise into the system.It is, therefore, the primary object of this invention, to provide apositive, automatic, mechanical means for preventing the pick up ofundesirable noise by soundpowered telephones when they are not beingused, although remaining connected in the telephone system.

It is another object of the invention to provide a mechanical means forautomatically closing the sound opening in a telephone receiver when thereceiver is removed from a listeners head and use thereof isdiscontinued, although the receiver remains connected to the telephonesystem.

It is also an object of the invention to provide an improved means forpreventing noise pick up by sound translatin devices as aforesaid whichis simple in construction, highly efiicient in use, and economical ofmanufacture.

The casing of a sound-powered telephone which houses the soundtranslating apparatus is customarily provided with an opening throughwhich sound waves generated by the translating apparatus can emerge fromthe casing and be heard by a listener when the telephone is held inproximity to the ear. For the purpose of preventing extraneous soundsfrom being heard by the listener, as well as to permit the instrument tobe worn with comfort, a flexible ear cap is usually attached to thecasing, such ear cap surrounding the casing opening.

In accordance with the present invention, a valve is provided forclosing the casing opening when the telephone receiver is not in use,the valve being normally biased to a closed position The flexible earcap is arranged to contact the valve so that, when external pressure isapplied to the ear cap (as when the ear cap is placed against the ear),it will withdraw the valve sufficiently from the casing opening toprovide a path or passage through which sounds can emerge.

The novel features that are considered characteristic of the invention,as well as additional objects and advantages thereof, will be understoodbetter from the following detailed description when read in connectionwith the accompanying drawing, in which Figure l is a front elevation ofa telephone unit .in accordance with my present invention,

Figure 2 is a cross section of the telephone unit shown in Figure 1,taken on the line 22, showing the valve in a closed position, and

Figure 3 is a fragmentary, sectional view similar to Figure 2 butshowing the valve in an open or withdrawn position.

Referring more particularly to the drawing, wherein similar referencenumerals are used to designate corresponding parts throughout, there isshown a sound-powered telephone unit I including a casing 3 havin aremovable cover or front plate 5. A vibratory element or diaphragm l isshown mounted within the casing 3 in spaced relation to the front plate5. Sound translating apparatus which may comprise an electromechanicalconverter 9 of any suitable kind is also mounted in the casing and isoperatively connected to the diaphragm l by means of a drive rod iii,the diaphragm and converter being adapted to function in a manner wellknown in the art.

An aperture or opening it is centrally located in the front plate orcover 5 for the purpose of permitting sound waves generated by thevibratory member 1 to emerge from the casing When a listener uses thedevice or unit I as a telephone receiver, the front plate 5 is heldagainst the car so that sound waves generated by the vibratory memberwill be transmitted directly to the auditory canal. For the purpose ofproviding an acoustic seal against extraneous noises, as well asproviding comfort for the wearer, an ear cap or flexible member !3 isattached securely to the front plate 5 by any suitable means. The earcap i3 is constituted of a soft, flexible material, such as spongerubber, or

an equivalent thereof which is capable of conforming easily to thecontour of the human car. A central opening l provided in the ear cap I3is in registry with the casin opening H and tapers outwardly toward theperipheral edges of the ear cap, as best seen in Figure 2.

For the purpose of closing or sealing the casing opening ii, in order toprevent undesirable sound waves, which originate externally of thereceiver I, from entering the casing 3 when the receiver is not in use,a valve or closure member 11 is provided. The valve comprises acylindrical portion I 9 disposed within the opening ll, an inner,disc-like portion 2| disposed on one end of the cylindrical portion, andan outer, resilient or spring-biased, disc-like portion 23 disposed onthe opposite end of the cylindrical portion. The cylindrical portion i9has a diameter smaller than the diameter of the casing opening H and alength greater than the thickness of the casing front plate 5. The innerand outer disc-like portions 2!, 23 have diameters greater than that ofthe casing opening II. The outer disc 23 is provided around itsperiphery, With a plurality of tabs or finger-like parts 25 which areresilient and bias the valve [7 outwardly from the receiver I byexerting pressure against the external surface 26 of the front plate 5.Thus, the outer disc 23 forces the inner disc 2|, which is locatedinside of the casing 3, against the internal surface 28 of the frontplate 5, thereby forming a closure or seal for the casing opening I I,as shown in Figure 2.

A plurality of apertures 21 are provided in the outer disc 23 for thepurpose of permitting sound waves, to be transmitted to the ear capopening i5 while the instrument is in use and the valve is in an open orwithdrawn position, as shown in Figure 3, the arrows 29 designating thepath of the sound waves.

In order to move the valve to an open position, the inner marginalportions 3| Of the ear cap [3 are in contact with the marginal portion33 of the outer disc 23 and the spring fingers 25. When the telephonereceiver is placed on the head of a listener, the ear cap I3 is placedin contact with the listeners ear. The head band (not shown), whichsupports the receiver, presses the receiver against the listeners earwith sufiicient force to press the ear cap l3 against the outer disc 23thereby flexing the spring fingers 25 and pushing the valve i'i inwardlyto an open position. When the receiver is removed from the listenershead, the valve l1, being spring "biased outwardly, will be returned toits normal, closed position.

It will, of course, be recognized by those persons skilled in the art,that the above-described telephone unit may be used as a microphone orsound-powered transmitter, as well as a receiver when used as atransmitter, the ear cap is pressed against the region of a user's faceabout his 7 mouth with suiflcient pressure to push the valve to an openposition, thereby permitting sound waves from his mouth to enter thecasing for actuating the diaphragm. In this case, the ear cap forms aneffective seal against extraneous sounds when it is in contact with theusers-face and prevents those sounds from entering the casing.

From the foregoing description, it will be apparent to those personsskilled in the art that'the invention provides a positive, automatic,mechanical means for preventing extraneous noises from entering thecasing of a sound-powered telephone receiver when the receiver is notbeing used as such although it remains connected into a telephonesystem. Although there is illustrated and described but a singleembodiment of the invention, it will be apparent to those skilled in theart thatother forms, as well as changes, are possible. Therefore, it isdesired that the particular form of the invention described herein beconsidered merely as illustrative and not as limiting.

What is claimed is:

1. In an acoustic device, the combination of a casing having an openingfor the passage of sound therethrough, a closure member movably mountedwithin said opening and normally biased to closing relation with saidopening for preventing the passage of sound therethrough, and a flexiblemember having an opening in registry with said casing opening carried bysaid casing,

said flexible member being in contact with said closure member and beingyieldable in response to external pressure for displacing said memberfrom its said closed relation with said casing opening to thereby leavesaid casing opening open for the passage of sound waves therethrough.

2. The invention set forth in claim 1 characterized in that said closuremember comprises a cylindrical portion disposed within said casingopening, an inner disc disposed within said casing and connected to oneend of said cylindrical portion, and an outer disc on the opposite endof said cylindrical portion external to said casing, and furthercharacterized in that said inner and outer discs have diameters greaterthan said casing opening.

3. The invention set forth in claim 2 characterized in that said outerdisc includes a plurality of resilient tabs which are in contact withthe exterior surface of said casing for biasing said closure memberoutwardly with respect to said casing and into said closed relation.

4. The invention set forth in claim 3 characterized in that said outerdisc is also provided with a plurality of openings in registry with saidear cap opening for the passage of sound waves transmitted through saidcasing opening, and further characterized in that the inner marginalportion of said flexible member contacts said outer disc adjacent saidresilient tabs.

5. Sound translating apparatus for use in contact with the human earcomprising a casing having an opening for the passage of sound throughone side thereof, sound translating means mounted within said casing,closure means extending through said casing opening and biased toprovide a closure for said opening when said apparatus is not in use,and a flexible ear cap carried by the exterior of said one casing sideand having an opening in registry with said casing opening, said ear capbeing in contact with said closure means for influencing said means awayfrom said casing opening when said ear contacts and presses against saidear cap thereby to permit passage of sound through said casing opening.

ALFRED H. KETTLER.

. 'No references cited.

